fix: recursively re-export nested submodules

modules/python/src2/typing_stubs_generation/generation.py

@@ -621,12 +621,17 @@ def _populate_reexported_symbols(root: NamespaceNode) -> None:
     # Re-export all submodules to allow referencing symbols in submodules
     # without submodule import. Example:
     # `cv2.aruco.ArucoDetector` should be accessible without `import cv2.aruco`
-    for submodule in root.namespaces.values():
+    def _reexport_submodule(ns: NamespaceNode) -> None:
-        root.reexported_submodules.append(submodule.export_name)
+        for submodule in ns.namespaces.values():
+            ns.reexported_submodules.append(submodule.export_name)
+            _reexport_submodule(submodule)
+
+    _reexport_submodule(root)
 
     # Special cases, symbols defined in possible pure Python submodules should be
     root.reexported_submodules_symbols["mat_wrapper"].append("Mat")
 
+
 def _write_reexported_symbols_section(module: NamespaceNode, output_stream: StringIO) -> None:
     """Write re-export section for the given module.